Spare area management method of optical recording medium

ABSTRACT

A spare area management method of an optical recording medium is disclosed. The spare area management method utilizes an identification information to indicate whether a primary spare area is full or a supplementary spare area has been assigned or extended, as necessary. Also, the present spare area management method improves the performance of the driver by replacing a defect block with a spare block nearer to the defect block.

This application is a continuation of application Ser. No. 09/443,319,filed Nov. 19, 1999, now U.S. Pat. No. 6,453,384.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an optical recording medium and moreparticularly, to a spare area management method of a rewritable opticalrecording medium.

2. Discussion of Related Art

An optical storage medium is generally divided into a read only memory(ROM), a write once read many (WORM) memory into which data can bewritten one time, and rewritable memories into which data can be writtenseveral times. Rewritable optical storage mediums, i.e. optical discs,include rewritable compact discs (CD-RW) and rewritable digitalversatile discs (DVD-RW, DVD-RAM, DVD+RW).

The operations of writing and playing back data in a rewritable opticaldisc may be repeated. This repeated process alters the ratio of storagelayers for recording data into the optical disc from the initial ratio.Thus, the optical discs lose its characteristics and generate an errorduring recording/playback. This degradation appears as a defect area atthe time of formatting, recording on or playing back from an opticalstorage medium. Also, defective areas of a rewritable optical disc maybe caused by a scratch on its surface, particles of dirt and dust, orerrors during manufacture. Therefore, in order to prevent writing intoor reading out of the defective area, management of such defective areasis necessary.

FIG. 1 shows a defect management area (DMA) in a lead-in area and alead-out area of the optical disc to manage a defect area. Particularly,the data area is divided into a plurality of zones for the defect areamanagement, where each zone is further divided into a user area and aspare area. The user area is where data is actually written and thespare area is used when a defect occurs in the user area.

There are four DMAs in one disc, e.g. DVD-RAM, two of which exist in thelead-in area and two exist in the lead-out area. Because managingdefective areas is important, the same contents are repeatedly recordedin all four DMAs to protect the data. Each DMA comprises two blocks of32 sectors, where one block comprises 16 sectors. The first block of theDMA, called a DDS/PDL block, includes a disc definition structure (DDS)and a primary defect list (PDL). The second block of the DMA, called anSDL block, includes a secondary defect list (SDL). The PDL correspondsto a primary defect data storage and the SDL corresponds to a secondarydefect data storage.

The PDL generally stores entries of defective sectors caused during themanufacture of the disc or identified when formatting a disc, namelyinitializing and re-initializing a disc. Each entry is composed of anentry type and a sector number corresponding to a defective sector. TheSDL lists defective areas in block units, thereby storing entries ofdefective blocks occurring after formatting or defective blocks whichcould not be stored in the PDL during the formatting. Each SDL entry hasan area for storing a sector number of the first sector of a blockhaving defective sectors, an area for storing a sector number of thefirst sector of a block replacing the defective block, and reservedareas. Accordingly, defective areas, i.e. defective sectors or defectiveblocks, within the data area are replaced with normal or non-defectivesectors or blocks by a slipping replacement algorithm and a linearreplacement algorithm.

The slipping replacement algorithm is utilized when a defective area isrecorded in the PDL. As shown in FIG. 2A, if defective sectors m and n,corresponding to sectors in the user area, are recorded in the PDL, suchdefective sectors are skipped to the next available sector. By replacingthe defective sectors by subsequent sectors, data is written to a normalsector. As a result, the user area into which data is written slips andoccupies the spare area in the amount equivalent to the skippeddefective sectors. For example, if two defect sectors are registered inthe PDL, the user area is slipped into two sectors of the spare area anddata may occupy such two sectors of the spare area.

The linear replacement algorithm is utilized when a defective block isrecorded in the SDL or when a defective block is found during playback.As shown in FIG. 2B, if defective blocks m and n, corresponding toblocks in either the user or spare area, are recorded on the SDL, suchdefective blocks are replaced by good blocks in the spare area and thedata to be recorded in the defective block are recorded in an assignedspare area.

When replacing defective area with the spare area by utilizing eitherthe slipping or linear replacement, the spare area may become full. Ifthe spare area becomes full, a spare full flag is set to indicate thatthe spare area is full.

In a disc structure as shown in FIG. 1, a spare full flag exists in eachzone and each spare full flag is set according to the status of thecorresponding zone, i.e. if the zone is full. Therefore, when the sparearea is required for a slipping or linear replacement, the spare fullflag is checked to determine if the spare area in the corresponding zoneis full, i.e. whether the spare full flag has been set. If the sparefull flag has been set, a spare area of a zone in which the spare fullflag has not been set is detected and utilized. However, if the sparefull flags in all zones have been set, i.e. there is no more spare area,a slipping or linear replacement cannot be executed.

The spare area may be allocated in each zone as described above or maybe allocated in a designated portion of the data area. As shown in FIG.3, the spare area may be allocated on the top portion of the data area.In such case, the spare area is called a Primary Spare Area SA 1.Namely, the data area excluding the primary spare area becomes the userarea.

The primary spare area is assigned in an initial formatting processwithout a logical sector number (LSN).

Thus, the primary spare area is assigned when a manufacturer producesthe optical disc or when a user initially formats an empty disc. Also,the size of the primary spare area depends upon the size of the userarea. For instance, to have an initial data recording capacity of 4.7GB, shown in FIG. 3, the primary spare area of 26 MB is assigned.Moreover, when defective sectors are registered in the PDL according tothe initial formatting or reformatting of the optical disc, data cannotbe recorded in those defective sectors, reducing the recording capacity.Therefore, to maintain the initial data recording capacity, a portion ofthe primary spare area equivalent to the defective sectors registered onthe PDL slips into or becomes a part of the user area during formatting.Accordingly, a physical sector number (PSN) of the user area to which avalue of LSN=0 is assigned varies depending upon the defective sectorsregistered on the PDL.

If the primary spare area becomes full by slipping or linearreplacement, as shown in FIG. 4A, a new spare area may be assigned, forexample near the end of the user area. Such additional spare area iscalled a supplementary spare area (SA-2). If the assigned supplementaryspare area also becomes full, an extension of the assigned supplementaryspare area may be made when necessary as shown in FIG. 4B.

As described above, the assignment of the primary spare is fixed whilethe supplementary spare area is newly assigned or extendable ifnecessary. However, in the disc structure as shown in FIGS. 4A and 4B,there is a need to indicate separately whether the primary spare area isfull, whether the supplementary spare area has been assigned, or thestatus of the supplementary spare area as it is extended.

SUMMARY OF THE INVENTION

Accordingly, an object of the present invention is to solve at least theproblems and disadvantages of the related art.

An object of the invention is to provide a spare area management methodof an optical recording medium which can indicate whether a primaryspare area is full and whether a supplementary spare area has beenassigned.

Another object of the invention is to provide a spare area managementmethod of an optical recording medium which can indicate whether thespare area is available for a linear replacement.

Additional advantages, objects, and features of the invention will beset forth in part in the description which follows and in part willbecome apparent to those having ordinary skill in the art uponexamination of the following or may be learned from practice of theinvention. The objects and advantages of the invention may be realizedand attained as particularly pointed out in the appended claims.

To achieve the objects and in accordance with the purposes of theinvention, as embodied and broadly described herein, a spare areamanagement method of an optical recording medium comprises assigning anarea for primary and supplementary spare area identification informationon the optical recording medium; indicating by means of a primary sparearea identification information whether the primary spare area is full;and indicating by means of a supplementary spare area identificationinformation whether the supplementary spare area is available.

Preferably, the supplementary spare area identification informationindicates whether the supplementary spare area is assigned before asupplementary spare area is assigned, and indicates whether thesupplementary spare area is full after a supplementary spare area isassigned. Also, if the primary spare area is full, the primary sparearea identification information indicates the full state of the primaryspare area.

If the supplementary spare area identification information indicatesthat the supplementary spare area has not been assigned, thesupplementary spare area is assigned and the supplementary spare areaidentification information is converted into a value which indicates theexistence of an available supplementary spare area. If the supplementaryspare area identification information indicates a full state of thesupplementary spare area and if the supplementary spare area isextendible, the supplementary spare area is extended and thesupplementary spare area identification information is converted into avalue which indicates the existence of an available supplementary sparearea.

According to another aspect of the present invention, a spare areamanagement method of an optical recording medium comprises linearlyreplacing a defect block with a spare block from any spare area of theprimary and the supplementary spare areas, depending upon the defectblock. Preferably, the data on the defect block is linearly replacedwith a spare block nearest to the position of the defect block. The dataon the defect block is linearly replaced with a spare block of the sparearea in which a linear replacement time would be shortest. Also, thedata on the defect block is linearly replaced with a spare block of aspare area which is not full.

These and other objects of the present application will become morereadily apparent from the detailed description given hereinafter.However, it should be understood that the detailed description andspecific examples, while indicating preferred embodiments of theinvention, are given by way of illustration only, since various changesand modifications within the spirit and scope of the invention willbecome apparent to those skilled in the art from this detaileddescription.

BRIEF DESCRIPTION OF THE ATTACHED DRAWINGS

The invention will be described in detail with reference to thefollowing drawings in which like reference numerals refer to likeelements wherein:

FIG. 1 shows a data area configuration of a general optical disc in therelated art;

FIG. 2A shows a slipping replacement method for a defect area in therelated art;

FIG. 2B shows a linear replacement method for a defect area in therelated art;

FIG. 3 shows a spare area assigned at the top portion of the data area;

FIGS. 4A and 4B show a supplementary spare area assigned and extended onthe disc where the primary spare area is assigned as in FIG. 3;

FIG. 5 shows a structured where flags are added to indicate whether aprimary spare area is full and a supplementary spare area is used on theoptical recording medium according to an embodiment of the presentinvention;

FIGS. 6A to 6C are exemplary views illustrating primary andsupplementary spare area flags whose values are varied in accordancewith the status of the primary spare area and the supplementary sparearea according to an embodiment of the present invention;

FIGS. 7A to 7C are another exemplary views illustrating primary andsupplementary spare area flags whose values are varied in accordancewith the status of the primary spare area and the supplementary sparearea according to an embodiment of the present invention; and

FIG. 8 shows a linear replacement of the data on a defect block with thespare area nearest the defect block in a defect area management methodof an optical recording medium according to the present invention.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

Reference will now be made in detail to the preferred embodiments of thepresent invention, examples of which are illustrated in the accompanyingdrawings.

The present invention is generally directed to a spare area managementmethod of an optical recording medium which can indicate by means ofidentification information whether a primary spare area assigned on thetop portion of data area is full or a supplementary spare area assignedon the bottom portion of the data area is available.

The identification information is recorded independently from theprimary and supplementary spare areas. In the present invention, for theconvenience of an explanation, the identification information forindicating whether the primary spare area is full will be called ‘aprimary spare area full flag’ and the identification information forindicating whether the supplementary spare area is assigned or availablewill be called ‘a supplementary spare area full flag’.

FIG. 5 shows a data structure where the primary and supplementary sparearea full flags are added on the optical recording medium according toan embodiment of the present invention. Particularly, the primary andsupplementary spare area full flags may be added on a non-used area ofthe DMA, particularly the SDL or DDS. The primary and supplementaryspare area full flags are added to indicate whether the primary andsupplementary spare areas are full, respectively.

For example, if the primary spare area is available, i.e. the spareblock for a linear replacement is left, the primary spare area full flagis reset to a value of ‘0’. If the spare block is not available, i.e.the spare area is full, the primary spare area full flag is set to avalue of ‘1’.

Unlike the primary spare area full flag, the supplementary spare areafull flag is set differently before and after an assignment of thesupplementary spare area. Namely, the supplementary spare area full flagis added to indicate whether the supplementary spare area has beenassigned before the assignment of the supplementary spare area, andadded to indicate whether the supplementary spare area is full after theassignment of the supplementary spare area.

For example, if the supplementary spare area has not been assigned, thesupplementary spare area full flag is set to a value of ‘1’, and whenthe supplementary spare area is assigned, the supplementary spare areafull flag is set to a value of ‘0’. After the supplementary spare areahas been assigned, however, if there is available area within thesupplementary spare area, i.e. the spare block for the linearreplacement is left, the supplementary spare area full flag remains thevalue of 0’. Thereafter, once the spare block is not available, i.e. thespare area is full, the supplementary spare area full flag is set to thevalue of ‘1’.

Also, the method of assigning and extending the supplementary spare areamay be classified into two methods. Generally, in the first methodaccording to the present invention, if the primary spare area is full,the supplementary spare area is assigned and if the assignedsupplementary spare area is full, the supplementary spare area isextended. In the second method according to the present invention, if apredetermined area, for example 1 MB, is left within the primary sparearea, the supplementary spare area is assigned and if a predeterminedarea is left within the supplementary spare area, the supplementaryspare area is extended.

The second method may utilize one active mode, in which thesupplementary spare area is assigned when the primary spare area isstill left, but is not used for the linear replacement until the primaryspare area is full. Similarly, the extended supplementary spare area isnot used for the linear replacement until the assigned supplementaryspare area is full. Namely, the one active mode means that the primaryand supplementary spare areas are not simultaneously active and when thesupplementary spare area is extended, the supplementary spare areas arenot simultaneously active.

The various states of the primary and supplementary spare area fullflags in the one active mode are shown in FIGS. 6A-6C and FIGS. 7A-7Caccording to the embodiments of the present invention.

Referring to FIGS. 6A to 6C, the primary spare area is assigned uponformatting, and if necessary, i.e. if the primary spare area is full,the supplementary spare area is assigned. Thereafter, if the assignedsupplementary spare area becomes full, the supplementary spare area isextended. In particular, upon formatting, the primary spare area fullflag is reset to a value of ‘0’and the supplementary spare area fullflag is set to a value of ‘1’, as shown in FIG. 6A. Next, if the primaryspare area is full for the linear replacement, the primary spare areafull flag is set to a value of ‘1’, also shown in FIG. 6A. Since theprimary spare area is not extendable, the primary spare area full flagremains the value of ‘1’, as shown in FIGS. 6B and 6C.

The identification information for the spare area which differentiatesthe assignment, full state and extension of the supplementary spare areais by means of the supplementary spare area full flag. For example, thesupplementary spare area full flag is initially set to a value of ‘1’ asshown in FIG. 6A in a state where the supplementary spare area has notbeen assigned. If the supplementary spare area is assigned as necessary,the supplementary spare area full flag is reset to a value of ‘0’. Thus,when the primary spare area is full and the supplementary spare area isnewly assigned, the primary spare area full flag remains a value of ‘1’and the supplementary spare area full flag is reset to the value ‘0’, asshown in FIG. 6B.

Thereafter, if the assigned supplementary spare area becomes full for alinear replacement, the supplementary spare area full flag is set to avalue of ‘1’, as shown in FIG. 6B. However, if the supplementary sparearea is extended, the supplementary spare area is then reset to thevalue of ‘0’. In other words, since the supplementary spare area isextendable, the supplementary spare area full flag is repetitively resetto the value of ‘0’ from the value of ‘1’ each time the spare area isextended, as shown in FIG. 6C. However, when the supplementary sparearea cannot be further extended, the supplementary spare area full flagmaintains at the value of ‘1’.

Referring to FIGS. 7A to 7C, in another example, the primary spare areais also assigned upon formatting, and the supplementary spare area isassigned if a predetermined area within the primary spare area is left.Thereafter, if a predetermined area within the assigned supplementaryspare area is left, the supplementary spare area is extended. Inparticular, upon formatting, the primary spare area full flag is resetto a value of ‘0’ and the supplementary spare area full flag is set to avalue of ‘1’, as shown in FIG. 7A. Next, if a predetermined area in theprimary spare area for the slipping or linear replacement is left, thesupplementary spare area is assigned. At this time, the supplementaryspare area full flag is converted from the value of ‘1’ to a value ‘0’,as shown in FIG. 7B. However, since the primary spare area is not full,the primary spare area full flag maintains the value of ‘0’. Once theprimary spare area becomes full, the primary spare area full flag is setto the value ‘1’. Because the supplementary spare area is assigned andextended in the one active mode, the supplementary spare area is notused for a linear replacement before the primary spare area becomesfull, even if the supplementary spare area has been already assigned.

Similarly, if a predetermined area within the assigned supplementaryspare area is left, the supplementary spare area is additionallyextended. At this time, the supplementary spare area full flag maintainsthe value ‘0’ since the supplementary spare area would not be in a fullstate due to the extension. If the supplementary spare area cannot befurther extended, the supplementary spare area full flag is set to avalue of ‘1’, as shown in FIG. 7C.

In the above embodiment, the supplementary spare area may not be furtherextended because data is recorded in the area needed for the extensionof the supplementary spare area. In such case, the supplementary sparearea full flag is reset to the value of ‘0’ if data recorded on the areato be extended is erased and thereby the supplementary spare area isextended. However, once the supplementary spare area cannot be furtherextended, the supplementary spare area full flag is set to a value of‘1’, as shown in FIG. 7C.

Moreover, since the supplementary spare area is assigned and extended inthe one active mode, the extended supplementary spare area is not usedfor a linear replacement before the assigned supplementary spare areabecomes full, even if the supplementary spare area is already extendedin a state where a predetermined area within the supplementary sparearea is left.

In the above embodiments, the primary spare area is assigned prior tothe assignment of the supplementary spare area. However, the primary andsupplementary spare areas may be simultaneously assigned upon aformatting, in which the primary and supplementary spare area full flagsare all reset to a value of ‘0’.

Furthermore, when the spare area is active in the one active mode, theperformance of a linear replacement may be degraded. Namely, the linearreplacement method is executed by moving an optical pick-up to and fromthe spare area to record the data of the defective block on areplacement block in the spare area. However, since the spare areaexists on certain parts of the data area, the replacement time periodfor a defective block far from the spare area can be substantial. Tosolve this problem, the spare area may be active in a two active mode.

When a defective block is discovered during a recording or playback ofdata to or from the optical disc in which a spare area has beenassigned, the defective block is replaced with a spare block of thespare area nearest to the defective block, as shown in FIG. 8. Byreplacing the defective block with a nearby spare area, the performanceof the driver can be significantly improved. At this time, if only theprimary spare area is assigned, the-primary spare area is used for alinear replacement. However, when both the primary and supplementaryspare areas are assigned, an appropriate spare area, i.e. a nearby sparearea, is used for a linear replacement.

In this two active mode, the data of a defective block is linearlyreplaced with a spare block of the spare area located at a positionwhich results in the shortest moving distance of the optical pick-up. Ifall assigned spare areas are active irrespective of whether the sparearea is the primary or supplementary spare area, and if a spare blockwithin the primary and supplementary spare areas is left, the data of adefective block is linearly replaced with a spare block of any areawithin the primary or supplementary spare area which meets the abovecriteria. For example, the data of a defective block on the innerperipheral side of an optical medium, i.e. near the top of the dataarea, is linearly replaced with a spare block of the primary spare area.On the other hand, the data of a defective block on the outer peripheralside of an optical medium, i.e. near the bottom of the data area, islinearly replaced with a spare block of the supplementary spare area.

Unlike the one active mode in the two (multiple) active mode, the entiresupplementary spare area would be active irrespective of whether an areais an extension. Also, when both the primary and supplementary spareareas are simultaneously active, the spare area to be used for a linearreplacement is determined by first checking whether each spare area isfull.

For example, if a defective block is nearer to the primary spare area,the primary spare area full flag is checked. At this time, if theprimary spare area full flag is set to a value of ‘0’ as shown in FIG.7A, the data of the defective block is linearly replaced with a spareblock of the primary spare area. On the other hand, if the primary sparearea full flag is set to a value of ‘1’, the supplementary spare areafull flag is checked. If the supplementary spare area full flag is setto a value of ‘0’ as shown in FIG. 7B, the data of the defective blockis linearly replaced with a spare block of the supplementary spare area.This is generally shown in FIG. 8.

Therefore, upon a detection of a defective block, if any one of thespare area is full, the spare area in the full state is not used for alinear replacement. Also, if the supplementary spare area isadditionally extended, the supplementary spare area full flag is resetto a value of ‘0’ until the supplementary spare area cannot be furtherextended, as described with reference to the one active mode. Thus, whenthe supplementary spare area cannot be extended, the supplementary sparearea full flag is set to a value of ‘1’ as shown in FIG. 7C.Accordingly, if both of the primary and supplementary spare area fullflags are set to the value of ‘1’, a defective block management cannotbe further performed using a slipping or linear replacement.

As set forth above, a spare area management method of an opticalrecording medium according to the present invention can indicate bymeans of an identification information whether a primary spare area isfull or a supplementary spare area has been assigned or extended, asnecessary. Thus, the present invention indicates when a linearreplacement cannot be executed because the spare area is in a fullstate. In addition, a spare area management method of an opticalrecording medium according to the present invention can replace adefective block with the spare block of the spare area nearer to thedefective block, thereby improving the driver's performance upon thelinear replacement. Moreover, the present invention is applicable to anyoptical or other type of medium having the same format with anassignment of primary spare area and a supplementary spare area.

The foregoing embodiments are merely exemplary and are not to beconstrued as limiting the present invention. The present teachings canbe readily applied to other types of apparatuses, systems, and/ormediums. The description of the present invention is intended to beillustrative, and not to limit the scope of the claims. Manyalternatives, modifications, and variations will be apparent to thoseskilled in the art.

What is claimed is:
 1. A spare area management method for an opticalrecording medium, the method comprising: assigning an area for a primaryand a supplementary spare area identification information on the opticalrecording medium; setting the primary and the supplementary spare areaidentification information to indicate the states of a primary sparearea and a supplementary spare area; and setting a supplementary sparearea full flag as the supplementary spare area identificationinformation to indicate whether the supplementary spare area isassigned, before an assignment of the supplementary spare area, whereinthe state of the supplementary spare area full flag varies depending onwhether the supplementary area is assigned, and setting thesupplementary spare area full flag to indicate whether the supplementaryspare area is full, after the assignment of the supplementary sparearea.
 2. A method of claim 1, wherein the primary spare areaidentification information is a primary spare area full flag.
 3. Amethod of claim 1, further comprising: setting a primary spare area fullflag as the primary spare area identification information to indicatethat the primary spare area is full when the primary spare area becomesfull.
 4. A method of claim 1, further comprising: setting thesupplementary spare area full flag to indicate that the supplementaryspare area is full when the supplementary spare area becomes full; andresetting the supplementary spare area identification information toindicate that the supplementary spare area is available if thesupplementary spare area is extended.
 5. A method of claim 1, whereinthe primary and supplementary spare area identification information isstored in a non-used area of a defect management area.
 6. A method ofclaim 1, wherein the primary spare area is active for a defective blockreplacement, and the supplementary spare area is active for a defectiveblock replacement if the primary spare area identification informationindicates a full state of the primary spare area.
 7. A method of claim1, wherein the primary spare area and the supplementary spare area aresimultaneously active for a defective block replacement.
 8. A method ofclaim 7, wherein the supplementary spare area identification informationindicates an available state of the supplementary spare area until thesupplementary spare area cannot be extended.
 9. A method of claim 7,further comprising: linearly replacing a defective block with a spareblock of either the primary spare area or the supplementary spare areawhich is nearer to the defective block.
 10. A method of claim 7, whereindata on the defective block is linearly replaced with a spare block ofeither the primary spare area or the supplementary spare area whichresults in a shortest linear replacement time.
 11. A method of claim 1,wherein the supplementary spare area full flag is set to a designatedvalue to indicate that the supplementary area has been assigned eventhough the primary spare area is not full.
 12. An optical recordingmedium comprising: a primary spare area identification information whichindicates the state of a primary spare area of the optical recordingmedium; and a supplementary spare area identification information whichindicates the state of a supplementary spare area of the opticalrecording medium, wherein the supplementary spare area identificationinformation includes a supplementary spare area full flag whichindicates whether the supplementary spare area is assigned, before anassignment of the supplementary spare area, and which indicates whetherthe supplementary spare area is full, after the assignment of thesupplementary spare area, and wherein the state of the supplementaryspare area full flag varies depending on whether the supplementary sparearea is assigned.
 13. A spare area management method for an opticalrecording medium, the method comprising: assigning an area for a primaryand a supplementary spare area identification information on the opticalrecording medium; setting the primary and the supplementary spare areaidentification information to indicate the states of a primary sparearea and a supplementary spare area, wherein the supplementary sparearea identification information includes a supplementary spare area fullflag; and setting the supplementary spare area full flag to a firstposition to indicate that the supplementary spare area has beenassigned, to a second position to indicate that the supplementary sparearea is full when the supplementary spare area becomes full, and to thefirst position to indicate that the supplementary spare area isavailable if the supplementary spare area is extended, wherein the stateof the supplementary spare area full flag varies depending on whetherthe supplementary spare area is assigned.
 14. A method of claim 13,wherein the supplementary spare area full flag is set to a designatedvalue to indicate that the supplementary area has been assigned eventhough the primary spare area is not full.
 15. An optical recordingmedium comprising: a primary spare area identification information whichindicates the state of a primary spare area of the optical recordingmedium; and a supplementary spare area identification information whichindicates the state of a supplementary spare area of the opticalrecording medium, wherein the supplementary spare area identificationinformation includes a supplementary spare area full flag which is setto a first position to indicate that the supplementary spare area hasbeen assigned, to a second position to indicate that the supplementaryspare area is full when the supplementary spare area becomes full, andto the first position to indicate that the supplementary spare area isavailable if the supplementary spare area is extended, and wherein thestate of the supplementary spare area full flag varies depending onwhether the supplementary spare area is assigned.
 16. An opticalrecording medium of claim 15, wherein the supplementary spare area fullflag is set to a designated value to indicate that the supplementaryarea has been assigned even though the primary spare area is not full.17. An optical recording medium comprising: an area assigned for aprimary and a supplementary spare area identification information; theprimary and the supplementary spare area identification information setto indicate the states of a primary spare area and a supplementary sparearea, wherein the primary spare area and the supplementary spare areaare simultaneously active for a defective block replacement; and theprimary spare area used for a defective block replacement if thesupplementary spare area identification information indicates a fullstate of the supplementary spare area, and the supplementary spare areaused for a defective block replacement if the primary spare areaidentification information indicates a full state of the primary sparearea.